Method and means for bending tubing



June 16, 1936. 5. F. OLIVER ET AL.

METHOD AND MEANS FOR BENDING TUBING- Filed June 16, 1934 3 Sheets-Sheet l fljm - INVENTORS. George F Oliver: Harry 6: Sahib:

ATTORNEYS.

June 16, 1936. G. F. OLIVER ET AL METHOD AND MEANS FOR BENDING TUBING Filed June 16, 1934 3 Sheets-Sheet 2 INVENTORS. George 7. 016 Var;- flarrg 6i ficfloliz.

BY 192% flaw y ATTORNEYS.

June 16, 1936.

G; F. OLIVER ET AL METHODAND MEANS FOR BENDING TUBING- Filed June 16, 1954 s Sheets-Sheet 5 INVENTORS. George F Ola'yer; Marry a Sc/mltz.

ATTORNEYS.

Patented June 16, 1936 UNITED STATES 2.044.822 rm'rnon AND mums ron ammo 'ronme George F. Oliver,

Wyandotte, Mlcln,

Corporation of America, a corporation of ware Application June 16,1934, Serial No. 130,886

11 Claims. (91- 153- 63) Our invention relates to methods and means for bending tubes and particularly to a method and means for progressively ironing out any deformation which may occur during a bending operation on tubing to maintain the cross-sectional shape of the tube throughout its length when the tube is bent to desired form.

Tubes have been bent heretofore by employing sand, resin, sulphur and like materials on the inside which resist the collapse of the tube during the bending operation. A spring type of bending die has also been employed for lead tubing to prevent the tube from buckling during the bending operation. Such materials and elements have speciflc application and could not be employed commercially on tubes of heavy gauge material to produce a bending operation effected by the method and means of the present invention.

In practicing our invention we employ a flexible sizer made up of a plurality of sizing blocks supported together on a flexible element such as a cable having a pulling head on one end. The blocks are inserted within the hollow tube and are constructed to have only a slight clearance to be effective during the bending operation to prevent the tube from buckling. This is accomplished by moving the sizing blocks in the tube during the time the bending operation is being effected by the dies. After the bending operation, the sizing blocks are removed and the tube is in exact predetermined shape which is that 0! the die, since, due to the working of the metal, the tube will not spring back and assume some other form. 7

We have shown, for the purpose of illustration, the sizing blocks being employed upon a chassis section and upon a complete chassis side frame element. A straight rectangular shaped tube is bent to have the body-sweep, the rear kick-up portion and the front bowed portion. This clearly illustrates the novelty of our invention and the advance made in the art of bending tubes.

Accordingly, the main objects of our invention are: to provide a set of sizing blocks in intimate flexible relation to each other within the confines of a tube to be bent; to provide a set of dies for bending a tube in a predetermined manner after the sizing blocks are disposed within the tube and moved therein during the time the tube is being formed by the dies; to provide a machine which simultaneously bends the tube, draws the sizing blocks therethrough and retains the tube clamped in the dies during the time the sizing blocks are withdrawn therefrom; to provide a machine for bending the tube in one dlrection to desired shape and for thereafter bending the tube in the opposite direction during the time the sizing blocks are moved therein to bend the I structure illustrated in Fig.- 8, taken i struction. In Figs. 2, 3 and 4 we tube both in the directionof its width and thickness; to provide two sets of flexible sizing blocks insertible from opposite ends of the tube to be moved during the bending operation; to provide a machine which effects the bending of a tube in both directions of its lateral dimensions, and, in general, to provide means for forming tubes to desired shapew 'chis simple in construction, positive in opera ion andeconomical of manufacture. I 10 Other objects and features of novelty of 'ourinvention will be either specifically pointed out or will become apparent when referring for a better understanding of our invention. to the following description taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a perspective view of a tube which is to be bent by our method and means,

Fig. 2 is a view, partly in section and partly in elevation, of means for bending the tubeillustrated in Fig. 1,

Fig. 3 is an enlarged sectional view of the structure illustrated in Fig. 2, taken on the line 3-4 thereof,

Fig. 4 is an enlarged sectional view of the'structure illustrated in Fig. 2, takenon the line 4-4 thereof,

Fig. 5 is a view of the tube illustrated in Fig. 1 after the bending operation,

Fig. 6 is an'enlarged broken view, partly in section, of the flexible sizing element illustrated in the tube in Fig. 2.

Fig. 7 is a plan view of a machine for effectin a further bending operation,

Fig. 8 is a view in elevation of the structure illustrated in Fig.7,

Fig. 9 is an; enlarged sectional view of the structure illustrated in Fig. 8, taken on the line 9-9 thereof, with the bending dies in closed position,

Fig. 10 is a view of the structure illustrated in Fig. 9, with the dies in open position,

Fig. 11 is an enlarged sectionalview of the on the line [1-11 thereof,

Fig. 12 is a broken top plan view, partly in section, of a portion of the structure illustrated in Fig. 11.

Fig. 13 is a plan view of the tube illustrated in Fig. '1 after the bending operation, and

Fig. 14 is a side view of the tube illustrated in Fi 13.

The tube It illustrated in Fig. 1 msstructed in any manner as by bending es and. a. welding operation, or by any other means known in the art to be suitable for forming tubing. The present invention does not, embody the construction of the tube itself but applies to the method of bending the tube after its conhave illustrated 6o be conbending dies comprising spaced apart metal blocks l6 which form a channel for receiving the width of the tube l5. At the bottom of the space between the two blocks a stationary die I1 is provided of a form in which the tube is to be bent. A movable die I 8 also of the width of the space between the blocks l6 anda shape complementary to that of the die I1, is supported on the movable head H! of the machine aligned with the die H in the space between the blocks IS. The blocks |6 are suitably supported on the base 2| of the machine. It is to be understood that the construction herein shown and described is for the purpose of illustration and is not a construction that would be used for rapid production commercially.

Referring more particularly to Figs. 2 and 6, a flexible sizing element 22 is provided made of a plurality of hard metal blocks23 which are of a width and thickness slightly less than the "inside dimensions of the tube l5. The blocks the cable 24, it is to be understood are strung on a flexible cable and are disposed within the confines of thet'ube i5. While we have illustrated the blocks as being strung'on that they could be so constructed as to be directly united to each other and still be within a degree of flexibility desired and that other means known in the art could be employed to form a unit element of the plurality of blocks 23'and at the sametime have the element flexible.

After the sizingblocks are disposed within the tube l the tube is pushed downwardly in the space between the blocks l6 and the end of the cable 24 is disposed over a sheave 25 having the end anchored on a pull block 26 which is disposed within a housing 21. The movable head H! of the machine carries a fork-like ram 28 which straddles the cable 24 andengages the upper face of the block 25. The block 26 may also carry a U-bolt 29 for :a purpose which will be explained hereinafter.

Upon the downward movement of the head l9, the die |8 starts bending the tube during the time the bifurcated ram 28 moves the block 26 within the housing 21. I This draws the cable 24 over the sheave to cause the blocks 23 to be moved'within the tube I5. This movement of the sizing blocks continues throughout thebending operation until the die tube I5 and die l8 are all in intimate engagement with each other. Thereafter the machine is stopped/and suitable pulling means is engaged to the U-bolt 29 to draw the cable and the sizing blocks from the tube, after which the head I9 is raised and the tube 5 is withdrawn from the space between the blocks I5.

The tube will then have the shape as illustrated in Fig.- 5 and will be uniform throughout its length having no buckles or crinkles therein because of the ironing of the metal'during the bending operation. In view of the fact that the metal is entirely worked throughout the bending operation, there will be no stresses or strains set up therein so that the metal will take a set at its final bent position and will not spring backto assume some other shape.

A further form of our invention is illustrated in Figs. 7 to 14, inclusivefwherein an entire chassis side frame of tubulalr section is bent-in two directions, one in the direction of the sweep of the body and onerelative to the vertical dimension of the body to provide the rear kick- The base 36 of the machine supports a complcmentary die 37, which, with the die 35, have a longitudinal curved shape 38, as illustrated in Fig. 7. The die 37 has a shouldered portion 35 for forming a channel with the die 34 for receiving the tube 30. The shoulder 39 is curved, conforming to the shape 4| of Fig. 8, in which the tube 30 is to be bent normal to the bend 38. A plunger die 42 is carried by the head 3| having its lower end of the shape 4| and bodily curved to conform to the shape 38. The relative lengths of the ram 32 and die 42 are such that the latter becomes effective only after the ram has completely, moved the die 35.

head 3|, the ram 32 causes the lateral movement of the die 35, through the engagement of the sloping faces 33 and 34 thereof, illustrated in Fig. 10 to effect the bend 38 in the tube 30.

Thereafter the plunger die 42 engages the tube 30 and, during the final movement of the head 3|, places the bends 4| therein. Suitable springs 43 may be employedto return the die to its initial position when the ram 32 is moved from engagement therewith. During the forming operations the sizing elements 22 are moved with-- in the tube to iron out any deformation which may be occurring during the downward and lateral movement of the ram portion 34 to prevent the buckling or cringling of the material. Figs. 13 and 14 illustrate the bends 38 and 4| which have been formed in the tube 30 by our method during a single movement of the head 3| of the bending machine.

For effecting the movement of the sizing element ZZ'IIOIII each end of the tube 30 we employ sheaves 4'! at each end of the die 31 over which the cables 24 extend to be engaged by a draw head 48 which is secured in ways 49 on the base of the machine. The draw head 48 is provided with a plurality of rack teeth 5| in engagement with a pinion 52 which is interconnectedby a shaft 53 to a pinion 54 which operates on a rack 55 connected to the head 3| of the machine. During the downward movement of the head the rack 55 operates the pinion 54 to rotate the pinion 52 and therefore to longitudinally move the draw head 48 for effecting the movement of the elements 22 Within the tube during the bending operation.

This may occur throughout the downward movement of the head to move the elements 22 in the tube 30 both during the movement to effect the bend 38 of the tube and also during the further movement to effect the bends 4| therein. A rod 56 may be attached to the head 48 to be moved v after the draw head 43 moves out of contact with the teeth of the pinion 52 to completely withdraw the element 22 from the tube 30 after the bending operation has been completed. Due to the severe working of the material after the bends 4| are placed therein, there will be no possibility of the material springing back to its original form and it will thereby assume the forms placed therein by the dies.

while we have shown the application of bending tubes as applied to chassis frames of automotive vehicles, it is to be understood that this is only for the purpose of illustration and that the invention may be applied to any type of tubing, of any cross section, to efiect the bending thereof without distortion. This method may be applied to square, round, polygonal, hexagon or any shape, the novelty of the invention being embodied in the ironing out of the wrinkles or distortions which may occur in the tubing during the time the tubing is being bent. This is clearly new and novel and is a material advance in the art of bending tubing, since the methods employed heretofore either attempted to prevent the crinkling of the material or ironed out the crinkles from the material after the bend occurred. In the present construction the bending and ironing occurs at the same time so that after the bending operation the tube is in desired shape which it will retain because of the warping of the material. At any time the material begins to fail the sizing blocks moving therealong will strengthen and iron out the bent portion so that the failure must occur at some other point. In this manner, any crinkles or buckles will be prevented from occurring to the material.

While we have described and illustrated but two embodiments of our invention, it will be apparent to those skilled in the art that various changes, omissions, additions and substitutions may be made therein without departing from the spirit or scope of our invention, as set forth in the accompanying claims.

We claim as our invention:

1. The combination with means for bendin the tube to the desired dimensions, of a sizing element disposed on the inner portion of the tube at the points to be bent, means for actuating said bending means to bend the tube and the sizing element, and means for moving said sizing element longitudinally through the tube during the time the bending operation is being effected.

2. The combination with means for forming a tube to desired dimensions, of a plurality of flexibly related sizing blocks disposed within the confines of said tube at the points to be formed, means for actuating said forming means to effect the bending operation and the shifting of the blocks, and means for moving said blocks longitudinally through the tube during the time of such movement of the forming means.

3. The combination with means for forming a tube to desired curvature, of a flexible sizing element disposed within said tube at the points to be formed, means for'moving said sizing element longitudinally through said tube, and means synchronized with said moving means for effecting the bending operation and the shifting of the element to follow the bend.

4. The combination with means for bending a tube in the direction of both of its lateral dimensions, of flexible sizing elements disposed in said tube, means for moving said bending means to first bend the tube in one direction and then in another and shift said elements following said bends, and means for moving said sizing blocks longitudinally in the tube during at least one of said bending operations.

5. The method of bending a tube in the direction of both of its lateral dimensions which includes the steps, of first bending the tube in one direction, thereafter bending the tube in the opposite direction, of supporting said tube against collapse during said bending operation, and during at least one of the bending operations ironing out any distortions which may occur to the material of said tube.

6. The method of bending a tube in two directions which includes the steps; of first bending the tube in one direction, of thereafter bending the tube in another direction, of supporting said tube against collapse dm'ing said bending operation, of ironing out any distortions of the metal of the tube during at least one of said bending operations, and of releasing said tube thereafter.

'I. The combination withv means for bending a tube in two dimensions, of bending means operable both downwardly and laterally, downwardly movable means for actuating said bending means, flexible sizing elements disposed within said tube, means for operating said downwardly moving means to first bend the material on the initial downward movement and through a further downward movement of said means to cause the tube to be bent in an opposite direction and the elements to be shifted following said bends, and means for longitudinally moving said sizing means in said tube during said bending operation.

8. The combination with means for bending a tube, sets of dies of the shape of said bends to receive said tube, a plurality of flexible sizing elements disposed in said tube, means for bending said tube in one direction, means for bending said tube in an opposite direction and cause said elements to shift following said bends, and means for longitudinally moving said elements in said tube during at least one of said bending operations.

9. The combination with means for bending a tube in two dimensions, of means for bending the tube in one direction, means for supporting the central portion of the tube against further bending movement, sizing elements disposed in the ends of said tube, means for bending each end of the tube in a direction opposite to the first bend and for shifting said elements to follow said bends, means for longitudinally moving said elements in said tube during at least one of said bending operations, and means for :hgreafter moving said sizing means from said 10. The method of bending tubes, which includes the steps, of first bending the tube in one direction, of thereafter bending the tube in the opposite direction, of preventing the collapse, of the tube during the bending operation, of ironing out any crinkles occun'ing in the metal of the tube during said bending operations, of removing said ironing means from said tube after the bending operation, and thereafter removing said tube from the bending means.

11. The combination with a machine for bending tubes, of means for releasably clamping the tube relative to a bending die which formsthe tube in one direction, means for bending the tube in an opposite direction to further form the tube, sizing blocks in said tube, means in addition to said dies for moving said blocks in said tube during at least one of said-bending operations, and means for removing the blocks and clamping means to have the formed tube entirely released in the machine.

GEORGE F. OLIVER. HARRY G. SCHOLTZ, 

